1. Field of the Invention
This invention relates to in general to plasma generating apparatus and method using a modulation system, and in particular to a plasma generating apparatus and method that increases inner uniformity of plasma within an ECR plasma apparatus or another ECR system applying etching or depositing process.
2. Description of the Prior Art
One type of semiconductor apparatus for commerical purposes is generally used for etching or depositing on the surface of semiconductor substrate.
A semiconductor substrate conducting apparatus which forms high density plasma by a magnetic field rotation is improved in uniformity. Also, the prior plasma reaction apparatus using a waveguide, a rectangle/round transformer transforms microwave energy from rectangular mode to circular mode, and then a plasma conducting apparatus which is improved in the multiformity of plasma creating density. FIG. 1 shows a schematic sectional, view illustrating ECR (Electron Cyclotron Resonance) structure of an prior art. At first, when two of a motion frequency are resonated (for example, when the frequency is same), the motion energy is maximum. Also, the plasma generating efficiency comes to the maximum. Hence, one of the motion frequency is able to rotation motion by magnetic field generating in magnetic coil, the other is rotated the receiving force by the microwave. For example, when the microwave is the frequency of 2.45 GHz and the magnetic field by magnetic coil is 875 Gauss, the resonance is occurred. In relation to above mentioned terms, as the part occurring resonance is limited, ion density of center portion of plasma is high and the peripheral of its is low. Then, as the plasma of prior making the above method is achieved etching or depositing so that the plasma is arrived wafer get out of the discharge window. Therefore, etching velocity or depositing velocity difference between wafer center part and the peripheral is large so that it have the disadvantage of multiformity of plasma creating density.